Well, obviously its convenient, like you said. I have many of them on auto withdrawl. Its also a good way to maintain a high credit score...I have just about optimal credit and I would like to keep it that way. It also allows you to accrue cash rewards and obtain preferred status. If I contest anything, they usually side in my favor.....if not I threaten to close the account. Finally, I also have a travel card, which allows me to accrue points towards reduced fare and such. This came in handy for the trip to Uganda....immense points. My wife is living off of that card over there until she comes home in Feb.